It carries it names really well. It does look like a torbedo. What are the dimentions of the outside case?

The second link is dead, by the way.

fixed ...

Quote:

Originally Posted by jdkJake

Nice pics TomB!
I think you already know what the next question is going to be....

Yes - dsavitsk and I are still working on it. The toroid reduced the noise by about 90%. Unfortunately, it's still detectable in certain headphones. We are going to try a few other specific things and let you know. I should have one of those things tried out this weekend and have the results.

I'm in the process of sending my toroid prototype over to Dsavitsk (it's taken awhile - been quite busy with non-headphone stuff, dang it!). He has a solder-desolder re-work station that has more capability than my equipment. I can't get the OT's removed without trashing them and the latest thing we were trying is to shield the OT's, which will require their removal. That's about as much as I can tell you right now.

I come from the solid-state department and would like to build the torpedo as a first tube project.

Since I alway wanted to built a point-to-point setup (I always admired the raw beauty of that), I wonder if there is any chance that the short kit is also available without case and pcb?

The custom transformers seem mandatory for this amp.

I guess, by building a separate enclosure for powersupply and amp, one can easily avoid the humming problem that may occur and still use the EI-core trafos.

Regards

Flo

We've reduced the hum significantly through the use of a toroid PT. I'm not sure whether we'll ever eliminate it completely with certain headphones, but that's not that unusual for tube amps in this price range.

Yes, the custom transformers are mandatory for this amp. Since the short kit from Beezar only contains the case, the PCB, and the transformers, you're essentially asking if you can just purchase the transformers. I think not, because we don't have "extra" stock. Besides, they are custom fabricated not only for the winding/turns ratios, but also for a PCB. The only connections are PCB pins.

Just an FYI, but one of the reasons the Torpedo is a safe alternative for building a tube kit is the use of the PCB.

Anyway, I would suggest that you refer to the several excellent articles that Dsavitsk authored on the L'esspresivo - that's what forms the basis of the Torpedo design with its PCB:

Maybe Dsavitsk will post with more details, but it's not really hum (60 Hz) - or even ripple (120 Hz). There's a small spike at around 180 Hz that has shown up for both of us in tests. Depending on the production variance of the OT's and certain headphones, that spike runs about 2dB into audibility. The difference is quite small and is essentially the difference with the lid on vs the lid off. The toroid is what brought this down to about 2dB audibility. The last thing we tried for removing it the rest of the way was shielding the OT's, but according to Dsavitsk, it made no difference.

Meanwhile, I have sold several of the short kits with the old PT while we were fooling aorund with the toroid. I have had no complaints and one individual is even selling them in "built" form. The last PT version I built was modified with the addition of a choke. I would highly recommend the choke on the non-toroid version. It may just be the choke adds extra metal inside the case and that "blocks" the interference, but the existing version is definitely quieter with a choke. Also, I put in some cheap Solens for the heck of it and amazingly, they sound every bit as good as the Clarity caps. I think that's more an indication that Dsvatisk's design is not as susceptible to quality cap changes, than any sort of luck with the Solens. Bottom line, I could tell no difference.

I have been listening to the non-toroid version almost exclusively for the last week or two. With my pupDAC and Grados or Sennheisers, it sounds wonderful. You practically have to train yourself to hear the "ripple." Even then, it seems to have no effect on the music.

Ok, I figured, that it would be too much to ask, selling the transformers separately. Of course I would be willing to buy the hole short kit as well (with the PCB and the nice case lying around useless afterwards), but in your post it sounds that the print-transformers could not be used properly in a point-to point setup.

I have to admit, I have never done a point to point setup, and I believe you that it could be difficult with the wrong parts. So, thank you for this information.

On the other hand, I have built anything solid state, from source to poweramp, so I am not afraid of high voltages.

Of course, I have already been reading into the mentioned links on the l´espressivo, but the choice of transformers seemed critical (and expensive, depending on the tranformer) for the use with grado headphones, so I thought I might just ask for the "stock transformer package" and maybe get a hint or two on the way.

I understand that, if a "non-stock" version of the torpedo is the aim, maybe this is the wrong tread to post, so I will do some reasearch of my own and maybe find help in another thread or forum.

BTW, it is not just about the (maybe noexisting) "hum" , but I really want to make a "diy wrapping" of the hole package.